Clean up Makefile to modern standards.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

Release 0.9.3:
-PLAIN mechanism is used only when no other mechanisms are supported
-Legacy authentication is disabled by default, can be enabled with connection flag
 XMPP_CONN_FLAG_LEGACY_AUTH
-Session is not established if it is optional
-Fixed a bug causing a reused connection not to cleanup properly
-Improved debug logging in OpenSSL module
-Few memory leaks fixed

Also fix some build flag

Signed-off-by: Chih-Wei Chen <changeway@gmail.com>

This helps packages depending on libs/libstrophe in finding the library via pkg-config or CMake's PKG_SEARCH_MODULE

Signed-off-by: Enrico Mioso <mrkiko.rs@gmail.com>

Switched from direct git to codeload. Should make it more reliable.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

fix Makefile chmod (644)
replace MD5SUM with HASH
add PKG_MIRROR_HASH when PKG_SOURCE_PROTO:=git

(PKG_SOURCE_PROTO:=svn tarballs are not reproducible for now)

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

Switch to git repo to properly set tarball filename

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>

Signed-off-by: Chih-Wei Chen <changeway@gmail.com>

Signed-off-by: Chih-Wei Chen <changeway@gmail.com>

Config.in for libxml2/expat XML library choice

Signed-off-by: Chih-Wei Chen <changeway@gmail.com>